class BankAccount:
    def __init__(self,account_number,balance):
        #账号名
        self._account_number = account_number
        #余额
        self.__balance = balance
    
    def __str__(self):
        return "账号:{} 余额:{}".format(
            self._account_number,
            self.__balance
        )
        
    def deposit(self,amount):  #存款
        self.__balance += amount
        
    def withdraw(self,amount): #取款
        if amount <= 0:
            print("金额异常,取不了")
            return
        if self.__balance < amount:
            print("余额不足")
            return
        
        self.__balance -= amount
   
account = BankAccount("12468",1000)
print(account)

account.deposit(200)
account.withdraw(300)
print(account)